1. Field of the Invention
This invention relates to a device for sealing puncture wounds in blood vessels, particularly the types of wounds that result from certain procedures in interventional medicine.
2. Description of the Related Art
A large number of medical therapeutic and diagnostic procedures involve the percutaneous introduction of instrumentation into a blood vessel. For example, percutaneous transluminal coronary angioplasty (PTCA), most often involving access to the femoral artery, is performed hundreds of thousands of times annually, and the number of other such vessel-piercing procedures performed, e.g., percutaneous coronary angiography and atherectomy, has exceeded two million per year.
In each event, the closing and subsequent healing of the resultant vascular puncture is critical to the successful completion of the procedure. Traditionally, the application of external pressure to the skin entry site by a nurse or physician has been employed to stem bleeding from the wound until clotting and tissue rebuilding have sealed the perforation. In some situations, this pressure must be maintained for half an hour to an hour or more, during which the patient is uncomfortably immobilized, often with sandbags and the like. With externally applied manual pressure, both patient comfort and practitioner efficiency are impaired. Additionally, a risk of hematoma exists, since bleeding from the vessel may continue until sufficient clotting effects hemostasis. Also, external pressure devices, such as femoral compression systems, may be unsuitable for patients with substantial amounts of subcutaneous adipose tissue, since the skin surface may be a considerable distance from the vascular puncture site, thereby rendering skin compression inaccurate and thus less effective.
Recently, devices have been proposed to promote hemostasis directly at the site of the vascular perforation. These devices can generally be grouped into two categories--"short-term" and "long-term".
Short-term devices are designed to improve on external pressure devices by applying pressure to the puncture site internally, for a limited period of time, after which the device is removed. An example of such a device is described in U.S. Pat. No. 5,383,896, issued on Jan. 24, 1995 to Gershony et al. That device consists of a shaft with an expandable balloon and guidewire tip at its distal end. A fixation collar on the shaft permits the device to be secured in place. In use, the distal end of the device is introduced into a blood vessel through an introducer sheath that is typically used in percutaneous interventional procedures. The balloon is then inflated and withdrawn until the balloon hemostatically engages the inner surface of the blood vessel, after which the introducer sheath is removed from the body. The fixation collar applies tension to the balloon for a medically sufficient period of time, after which the balloon is deflated and the entire device is removed from the body.
U.S. Pat. No. 5,645,566, issued on Jul. 8, 1997 to Brenneman et al., discloses a device that applies pressure to the outside wall of the punctured blood vessel from a distance of about 2 mm to 10 mm from the wall. It discloses various devices for applying the pressure--a balloon, a sheet supported at its corners by prongs, and a foam pad. It also describes various ways to locate accurately the pressure-applying device, such as a balloon in the vessel (similar to that of Gershony et al.) and the use of a radiopague marker.
PCT Application WO 98/11830, published on Mar. 26, 1998, S. Barak, Inventor, discloses various embodiments of an apparatus for hemostasis. Among them is a device that positions an "anchor" against an inner surface of an artery wall and a balloon outside the wall. The balloon is inflated to pinch the artery wall, after which the anchor is withdrawn. The balloon is maintained against the puncture until hemostasis is achieved.
Long-term devices are fabricated of bioabsorbable materials and are intended to remain in the body until they are absorbed. Two of these devices are available commercially, under the trademarks Angio-Seal.TM. (Kensey Nash Corp., Exton, Pa.) and Vasoseal.TM. (Datascope Corp., Montvale, N.J.).
Angio-Seal is a bioresorbable device that deploys an anchor against the inside of an artery wall and a compressed collagen sponge on the outside of the wall. The anchor and sponge are linked by a suture. (See U.S. Pat. Nos. 5,282,827 and 5,662,681).
The Vasoseal vascular hemostatic device is generally described in U.S. Pat. No. 5,391,183, issued on Feb. 21, 1995 to Janzen et al. The device inserts hemostatic material through a tissue channel and against the outside wall of the blood vessel around the puncture site.
U.S. Pat. No. 5,690,674, issued on Nov. 25, 1997 to Diaz, discloses a biodegradable plug that has two substantially parallel disks that are joined at their centers by a waist. The plug is positioned so that the distal disk is on the interior wall of the blood vessel, the proximal disk is on the exterior wall, and the waist in the wound of the vessel wall.
A description of the medical context for this invention, as well as a description of many of the prior art devices, appears in U.S. Pat. No. 5,810,884, which is hereby incorporated herein by reference. These devices typically suffer from one or more problems. They may be bulky, difficult to use, and expensive and they are not always effective at eliminating blood seepage. In some, the device may be spaced too far from the outside wall of the vessel, where there is a danger that a pseudo aneurysm may form. In others, if the device intrudes into the vessel, intravascular clots and/or collagen pieces with thrombus attached can form and embolize downstream to cause vascular occlusion. The present device addresses these problems.